how to develop a download file in html code example

Example: how to make a html file downloader

<!--button-->

<button onclick="save('NAME.html','CODE')"></button>

<script>
function save(filename, html) {
  var el = document.createElement('a');
  el.setAttribute('href', 'data:text/html;charset=utf-8,' + encodeURIComponent(html));
  el.setAttribute('download', filename);
  el.style.display = 'none';
  document.body.appendChild(el);
  el.click();
  document.body.removeChild(el);
}
</script>

<!--or-->
<!--link-->
<a href="the/name/of/your/file.x" download>